Crown control for rolling mill



March 19, 1968 STONE 3,373,588

CROWN CONTROL FOR ROLLING MILL Filed Aug. 17, 1965 2 Sheets-Sheet 1INVENTOR MORRIS D. STONE ATTORNEY March 19, 1968 M. D. STONE 3,373,588

CROWN CONTROL FOR ROLLING MILL- Filed Aug. 17, 1965 ZSheets-Sheet 2MORRIS D. STONE FIGZ Midi;

HI ATTORNEY United States Patent 3,373,588 CROWN CONTROL FOR ROLLINGMILL Morris Denor Stone, Pittsburgh, Pa., assignor to United Engineeringand Foundry Company, Pittsburgh, Pa., a corporation of PennsylvaniaFiled Aug. 17, 1965, Ser. No. 480,398 2 Claims. (Cl. 72--237) ABSTRACTOF THE DISCLOSURE The invention relates to a rolling mill having ahousing in which there is formed a window. The rolls of the mill areprovided with bearing chock assemblies which are received in the windowof the housing. Outward of the bearing chock assemblies, the rolls areengaged by piston cylinder assemblies designed to apply a bending forceon the rolls to bend them in a direction to increase the crown of therolls. The bending forces generated by the piston cylinder assembliesare isolated from the housing by providing rigid beam members arrangedbetween the bearing chock assemblies and the housing insuch a mannerthat the bending forces are self-contained, and wherein the improvementcomprises providing piston cylinder assemblies designed to apply abending force on the rolls to decrease the crown of the rolls, thelast-mentioned piston cylinder assemblies being carried in the beammembers so that the resultant forces thereof are taken by the beammembers and not by the housing of the mill. In addition piston cylinderassemblies are provided between the bearing chock assemblies to resistthe bending loads of the cylinders that exert a pressure to decrease thecrown.

This invention relates to a rolling mill, and more particularly, to amill incorporating roll deflection compensating mechanism, that is acrown control mechanism. One form of mechanism for compensating for thedeflection of the rolls of the mill, which deflection results in lateralgauge inaccuracies, is to impose a counteracting bending force on therolls to resist their tendency to deflect under the rolling loads. Asuccessful device of this type is illustrated in US. patent applicationSer. No. 468,468 entitled, Crown Control for Rolling Mill, filed June30, 1965, by J. W. OBrien.

In OBriens patent application, to speak for a moment with respect to theupper portion of the mill, an independent beam is provided between themill screws and the top backup roll of a four-high mill. The beam issubject to both forces required to. bend the roll and the reaction ofthe force which, while equal, is exerted in an opposite direction. Inthis way the roll bending forces are self contained and not imposed uponthe housings or screws of the mill and as a result avoid what can be avery serious problem in certain types of mills incorporatingcompensating mechanism for roll deflection.

In the foregoing arrangement, however, the backup rolls can be bent ordeflected in only one direction; namely, in a direction so that the rollbodies are urged towards the roll gap. This can represent a substantiallimitation on the crown control capacity of the roll compensatingdevice. For obvious reasons the elements involved in flexing the rollsto compensate for their deflection, can only compensate for deflectionsin one direction a limited amount of failure and fatigue of the partsare to be avoided.

It is one of the objects of the present invention to overcome theaforesaid limitation by providing a mill construction which will allowthe roll bending forces to be applied in both directions, whereby thecrown control capacity will be double that realized heretofore.

It is another object of this invention to provide in a rolling millincorporating a crown control mechanism and beam construction asdisclosed in the aforesaid US. patent application Ser. No. 468,468, asecond roll bending mechanism for bending the roll in a direction todeflect the roll body away from the roll gap, wherein said mechanism isarranged so that its reaction force is also taken by the beam, togetherwith means for resisting the roll being displaced towards the roll gap.

It is a still further object of this invention to provide in a rollingmill incorporating a crown control mechanism and beam construction asdescribed in the aforesaid US. patent application Ser. No. 468,468, asecond roll bending mechanism for bending the roll in a direction todefiect the roll body away from the material, wherein said mechanism isarranged so that its reaction force is also taken by the beam, whereinthe material itself resists the bending force thus serving as a fulcrumfor the roll bending forces.

In one form of the invention there is provided in a four-high mill forrolling material a pair of working rolls, each working roll having abackup roll, all of which are provided with chocks which are received inand supported by spaced-apart housings, a pair of power-operated millscrews received in said housings for moving the upper pair of rollstowards the lower ones, two beams extending between the housings andlocated as to the upper Ibeam between the screws and the adjacent backuproll and as to the lower beam between the housings and the adjacentbackup roll, said upper beam being engaged by said screws and the chocksof the upper backing roll, a first forceexerting means connected to theends of each backup roll for applying a bending force on the rolls in adirection to resist their tendency to deflect away from the material andthereby having the effect of increasing the crown of the rolls, thereaction force of said first force-exerting means being taken by saidbeams, a second force-exerting means including a first means connectedto the ends of the backup rolls and second means spaced inwardlytherefrom engaging the backup chocks of the backup rolls for applying abending force to the rolls in a direction to augment their tendency todeflect away from the material and thereby having the effect ofdecreasing the crown of the rolls, the reaction force of said secondforce-exerting means being taken by said beams.

These objects, as well as others, will be more readily understood whenthe following specification is read in light of the accompanyingdrawings of which:

FIGURE 1 is an elevational view, partly in section, of a four-high millillustrating one embodiment of the present invention, and

FIGURE 2 is an end elevational view ofthe mill shown in FIGURE 1,certain components of the mill being shown in section.

With reference to these drawings there is illustrated a four-high millcomprising two vertically arranged, spacedapart housings I1 and 12, thehousings having customary windows 13 and 14, into which is received apair of work rolls 15 and 16, each work roll being backed up in turn bya backup roll 17 and 18, respectively. Either or both of the pairs ofrolls are provided with a machine crown, which crown or crowns willincrease or decrease by the selective employment of the crown controlsystem of this invention.

As shown best in FIGURE 2, the journals of each roll are received inbearing checks, the work roll chocks being identified by the number 21and the backup bearing chocks by the number 22. In the customary mannerthe work rolls are urged away from each other and against theirrespective backup rolls by balance piston cylinder assemblies 23 mountedin the lower work roll chocks 22. In addition to these piston cylinderassemblies, between the backup roll chocks 22 and mounted in the lowerchocks, there are provided a pair of piston cylinder assemblies 24 oneach side of the mill. Each pair of these cylinders are directlyconnected with one of the cylinders of the second crown controlforce-exerting mechanism, yet to be described, and delivers the sameforce as the seconcl force-exerting mechanism. In this manner, the rollsare prevented from forcibly contacting each other and causing damage tothemselves and the associated parts.

With reference now to the upper portion of the mill, it will be notedthat between the housings and extending through the windows 13 and 14there is a horizontally arranged beam 25 in which, for brevitys sake,reference will be made to only one side of the mill. The lowersurface-of the beam in the vicinity of the chock 22 is provided with arocker plate 26 which engages a similar rocker plate 27 formed on thetop of the adjacent backup roll chock. Directly across from the areawhere the beam engages the chock and on its upper surface there isprovided a raised portion which receives a breaker block 28, the top ofthe breaker block having a spherical surface which is engaged by acomplementary surface formed at the bottom of the screw 29. The screw 29is received in a nut 32 formed in the housing 11, the screw beingrotated sly a worm and wheel not specifically shown on the drawngs.

Drawing attention now specifically to the beam 25, as shown in FIGURE 1,the center is connected to a rod 33, which extends in a verticaldirection. To the upper end of the rod 33 there is connected a piston 34of a piston cylinder assembly 35 mounted on a separator 36 that connectsthe housings 11 and 12 together at the top of the mill. The pistoncylinder assembly 35 is employed to urge the chocks 22 against the beam25 and the beam against the screws 29. To this end, the beam at itslower end is provided with opposed downwardly extending hooks 37 whichcooperate with projections 38 formed at the top of the chocks 22,whereby in operation of the piston cylinder assembly 35 the hooks engagethe chocks and bring them into contact with the bottom of the beam.

Still referring to the top of the mill, it will be noted that at theouter portion of the housings there is provided at each side of the millcylinders 41 which, as shown at the left of FIGURE 1, receives twopistons, 42 and 43, one extending from the top of the cylinder and theother extending from the bottom. The cylinders and piston constitute thefirst force-exerting crown control mechanism for the top backup roll andare employed as previously noted to deflect the backup roll towards thematerial, that is to effect an increase in the machine crown of therolls.

The lower piston 43 engages a rocker plate 44 carried by the beam 25,the rocker plate being provided with a spherical surface whichcooperates with a spherical surface formed at the end of the piston,thereby allowing for any relative movement between the two pieces. Theupper piston 42, as shown best in FIGURE 2, is connected to a crossmember 45, to the ends of which there are connected identically pivotallinks 46 which extend downward of the rolls on the outside of thewindows 13 and 14.

With reference now to the upper backup roll 17, and in still referringto but one side of the mill, it will be noted that outward of its mainbearing chock 22, there is provided a second bearing chock 47 which, asshown in FIG- URE 2, is provided with opposed projecting horizontalwings 48. The lower ends of the links 46 are formed so .as to engage thewings 48 of the bearing chock 47 whereby :the bending force exerted bythe cylinder 41 through the piston 42 is imposed upon the end of theroll 17 causing the center portion of the roll to bend in the directionof the work roll 15.

It will be appreciated that upon the operation of the cylinder 41, aforce is imposed upon the beam 25 by the piston 43 in a direction towardthe work roll and a force is imposed upon the roll by the piston 42which imposes a second force upon the beam in a direction opposite fromthe first force. Hence, there is a closed force circuit de velopedwhereby not only are there not any reaction forces 4' imposed upon thehousings 11 and 12, but the screws 29 are rendered free from any bendingforces.

Turning now to the second force-exerting mechanism for controlling thecrown of the backup rolls 17 and 18, and in still referring to the upperportion of the mill and one side thereof, FIGURE 1 illustrates thatbetween the ends of the backup roll 17 at each side of the mill andthebeam 25 is a second force-exerting means in the form of a pistoncylinder assembly 49. The rod end of the piston engages the top of thebearing 47 against which it applies a force to deflect the roll 17 andeffect a subtraction of the machine crown of the roll. The cylinder, inturn, is secured to the bottom of the beam 25 so that the beam receivesthe reaction forces of the cylinder. The pressure of the fluid fed tothe piston cylinder assembly 49 as well as its effective pressure area,equals that of the pair of piston cylinder assemblies 24 and theassemblies are directly tied together so that any change in the pressureof the cylinder 49 would effect a change in the pressure of thecylinders 24.

A generally similar arrangement is provided for the lower backup roll,in which connection there is a lower beam 51 which extends between thehousings 11 and 12 and through the windows 13 and 14 thereof, this beingbest shown in FIGURE 1 which also shows that the beam carries thebearing chocks 22 of the lower backup roll 18. F or completion of thedescription and in referring to one side of the mill, it will be notedthat the chock 22 is separated from the beam by a series of fillerplates 52 which are replaceable so as to compensate for the variousdiameters of the rolls employed in the mill. This, of course, is quitecustomary in mill design. FIGURE 1 also shows the relationship betweenthe beam 51 and the housing 11 wherein the beam rests upon the housing,there being rocker plates 53 provided so as to allow for relativemovement between these two elements. Outward of the ends of the beamthere are provided on the housings 11 and 12, cylinders 54. Thecylinder, in referring to one side of the mill, as in the case of thecylinders 41, is provided with two opposite arranged pistons 55 and 56,55 being the upper piston which engages the lower surface of the beam 51through a spherical bearing block 57 provided for allowing for relativemovement between the beam and the piston 55. The piston 56 extendsdownwardly from the cylinder 54 and is connected to a cross member 58,to which are pivotally secured at its outer ends, elongated links 59extending toward the work roll in such a way as to be clear of thewindows 13 and 14.

Outward of the main bearing chock 22 of the lower backup roll 18 is asecond bearing chock 62, the chock of which, as shown in FIGURE 2, hashorizontal wings 63 engaged by the links 59 and through which means thebending force of the piston cylinder assembly 54 is applied to the lowerbackup roll 18 in a way to bend the central portion of the roll in adirection of the lower work rolls 16. This arrangement, as in thearrangement provided for the upper backup roll 17, provides a closedforce circuit wherein the piston 55 imposes a force on the beam 51 inone direction and the piston56 imposes an equal, but opposite, force onthe beam through the chock 22, whereby the bending forces are selfcontained and are not imposed upon the housings 11 and 12.

As shown in FIGURE 1, the lower backup roll 18 is also provided with asecond force-exerting mechanism which takes the form of a pistoncylinder assembly'64 at each side of the mill. As in the case of thepiston cylinder assemblies 49 at the top of the mill, the cylinders ofthe assemblies 64 are carried by the beam 51 and the piston thereofengages the adjacent surf-ace of the outer bearing 62 of the lowerbackup roll 18.

In operation the first force-exerting cylinders 41 and 54 will beoperated in unison whenever it is desired to in crease the effectivecrown of the roll. To decrease the effective crown of the rolls, thecylinders 49 and 64 will be operated in unison.

It will be appreciated that various components of the mill illustratedhave not been referred to since they are quite common and that someelements have not been shown, since again they are Well known in theart. It will be further appreciated that while the present invention hadbeen illustrated in connection with a four-high mill, it may be used inother types or mills as well as other types of processing equipment,such as rubber and paper calenders.

In accordance with the provisions of the patent statutes, I haveexplained the princple and operation of my invention and haveillustrated and described what I consider to represent the bestembodiment thereof. However, I desire to have it understood that Withinthe scope of the appended claims, the invention may be practicedotherwise than as specifically illustrated and described.

I claim:

1. In a rolling apparatus including:

a pair of cooperative material reducing rolls having central portionsadapted to deflect away from the material being rolled under the rollingloads, the shape of the central portions of said rolls defining crownsof the rolls,

a housing having a window for receiving the rolls,

bearing chock assemblies mounted on the ends of the rolls for rotatablysupporting the rolls in said housat least one of said rolls havingopposed end portions extending outward of said bearing chock assemblies,

a cross member arranged parallel to said one roll and between itsbearing chock assemblies and said housing and having portions extendingoutward of the bearing chock assemblies of said one roll,

first force exerting means for each extending portion of said one rollhaving displaceable elements connected to the roll extending portionsfor imposing bending forces thereon to add to the crown of the roll andcause the central portion of said roll to deflect in a direction towardsthe material,

said first force exerting means arranged with respect to said crossmember that the reaction forces exerted by the displaceable elements aretaken by the cross member and not by the housing,

the improvement comprising a second force exerting means for eachextending portion of said one roll having displaceable elementsconnected to the roll extending portions for imposing bending forcesthereon to subtract from the crown of said one roll and cause thecentral portion of said roll to deflect in a direction away from thematerial, and

pressure exerting means arranged between said bearing chock assembliesconstructed and arranged to resist displacement of said one roll in adirection towards the material upon applying the bending force by saidsecond force exerting means.

2. In a rolling mill according to claim 1 wherein said means forresisting displacement of said one roll includes piston cylinderassemblies arranged between an opposed pair of bearing chock assemblies,said piston cylinder assemblies arranged to provide equal and oppositeforces with respect to the forces exerted by the second force exentingmeans.

References Cited UNITED STATES PATENTS 1,935,091 11/1933 Iverson 72-2453,171,305 3/1965 Stone 72-241 3,212,314 10/1965 Sieger 72225 CHARLES vV.LANHAM, Primary Examiner. A. RUDERMAN, Assistant Examiner.

